Suppression of the slow emission component in pure CsI by heat treatment

The heat treatment of annealing process for pure CsI crystals at 75°C has resulted in a significant decrease in the slow emission component compared with the crystals kept at room temperature. By observing the quenching of the heat treatment, it is found that the annealing temperature to suppress the slow emission component should not be higher than 150°C. The experimental results on the emission spectra of pure CsI crystal under gamma-ray excitation and alpha-particle excitation seem to provide a strong argument in favor of the intrinsic vacancy model on the origin of the slow emission component.